Work indexing mechanism for automatic sewing machine unit



April 11, 1967 U C JR ETAL 3,313,255

WORK INDEXING MECHANISM FOR AUTOMATIC SEWING MACHINE UNIT Filed Nov. 24. 1961 5 Sheets-Sheet 1 INVENTORS Lionel J. Coulombe mm 1 mm g Edward A Rauschdr.

WITNESS V l I I W TTORNEY April 1967 E. A. RAUSCH, JR, ETAL 3313,25

WORK INDEXING MECHANISM FOR AUTOMATIC SEWING MACHINE UNIT 5 Sheets-Sheet 2 Filed Nov. 24, 1961 INVENTORS Lionel J. Coulombe Edward A. Rausch, Jr. I 1, 2;

WITNESS TTORNEY Aprii 11, 1967 E, RAUSCH, JR" ETAL 3,313,255

WORK INDEXING MECHANISM FOR AUTOMATIC SEWING MACHINE UNIT 5 Sheets-Sheet 5 Filed Nov. 24, 1961 INVENTORS Lionel J. Coulombe Edward A Rausch, Jr.

WITNESS ATT RNEY United States Patent ()fiice f fiii WGRK INDEXING MECHANISM FOR AUTO- MATIC SEWZNG MACHINE UNIT Edward A. Rausch, Jr., Newark, and Lionel J. Coulornhe,

Matawan, N.J., assignors to The Singer Company, Elizaheth, N.J., a corporation of New Jersey Filed Nov. 24, 1961, Ser. No. 154,726

Claims. (Cl. 112-2) This invention relates to sewing machine units capable of automatically completing a plurality of spaced stitch groups such as buttonholes on a work fabric, and more particularly to a novel and improved work indexing mechanism for a sewing machine unit of the above character.

Reference is made to the co-pending United States patent of M. R. Kelemencky, Patent No. 3,053,204, dated Sept. 11, 1962 which relates to a sewing machine unit capable of automatically completing a plurality of spaced stitch groups in a work fabric. In the Kelemencky construction, movement of the work fabric is controlled alternately by the sewing machine work clamp, which dictates the fabric movement during stitching operations, and by the work grippers of the indexing mechanism which dictate the fabric movement between stitching operations and thus control the spacing and arrangement of adjacent stitch groups.

In sewing machine units of the above character, a problem arises in preventing interference between the work shifting means of the sewing machine and that of the indexing means. The Kelemencky patent teaches one solution to this problem in the provision of means for coupling the sewing machine work clamp with the fabric supporting portions of the work indexing mechanism so that the two move in concert during sewing. The resulting stress concentration on the work clamp, however, is high and the work clamp is apt to bind because the work grippers of the work indexing mechanism shift relatively to the sewing machine from one side to the other of the work clamp.

It is an object of this invention to provide a means for preventing interference between the sewing machine work clamp and the work indexing mechanism by automatically shifting the grippers of the work indexing mechanism just prior to the sewing operation so as to provide slack in and thereby freedom of movement of the work fabric sufiicient to accommodate the sewing machine work clamp travel.

Another object of this invention is to provide means for positively returning the grippers of the work indexing mechanism to work tensioning position on completion of each sewing operation so as to provide accurate indexing of the work fabric between stitch groups.

It is an object of this invention to obviate the imposition of any force or stress whatever on the sewing machine work clamp or work clamp shifting mechanism incident to the operation of the above referred to mechanism for providing slack in the work fabric adjacent to that portion held by the work clamp during the sewing operation.

It is a more specific object of this invention to provide a means for effecting the aforementioned slack producing shift of the work indexing grippers and for the return of the work indexing grippers in response to the operation of the sewing machine actuating mechanism as for instance the stop motion mechanism and in a manner such that the forces required of the sewing machine actuating mechanism to produce such slack remain substantially constant in all positions of the work indexing mechanism.

With the above and additional objects and advantages in view as will hereinafter appear, this invention will now be described as embodied in a preferred embodiment illustrated in the accompanying drawings in which:

FIG. 1 represents a side elevational view of a portion of a sewing unit, including a sewing machine in association with a work indexing mechanism, illustrated partly in vertical cross section, and having the present invention applied thereto,

FIG. 2 represents a front elevational view of a portion of the sewing unit illustrated in FIG. 1,

FIG. 3 represents a top plan view of the sewing unit of FIG. 1, with portions of the sewing machine broken away to expose the stop motion mechanism, and

FIG. 4 is an enlarged cross sectional view taken substantially along line 44 of FIG. 3.

As illustrated in the drawings, the sewing unit to which this invention is applied comprises a cabinet 11 containing an indexing mechanism (not shown), a sewing machine 12 carried on the cabinet, and a support plate 13 on the cabinet which carries the instrumentalities necessary to shiftably constrain a traveling work holder 14 relatively to the sewing machine.

The sewing machine 11 includes a work clamp 15 which may be closed to grip the work fabric, may be shifted in a closed path during sewing as for instance in a buttonhole shaped path, and may be opened to release the work fabric upon completion of stitching. The sewing machine needle 17 and a loop-taker 18 may be of conventional type stitch forming instrumentalities driven in timed relation with each other and with motion imparted to the work clamp 15 to form predetermined stitch groups. The sewing machine stitch forming instrumentalities and the work clamp are driven from a sewing machine actuating mechanism including a main drive shaft 24. The sewing machine actuating mechanism also includes a stop motion mechanism including a swinging stop motion frame 2% fulcrumed on the sewing machine at 21 and carrying a stop plunger 22 which is moved, when the stop motion frame is turned clockwise as viewed in FIG. 1, into the path of a lug 23 fast on the sewing machine main shaft 24. The stop motion frame also carries a belt shifter 25 which is moved, when the stop motion frame is turned clockwise, as viewed in FIG. 1, so that the belt controlled thereby runs on a loose idler pulley 26 on the main shaft. When the stop motion frame is shifted counterclockwise as viewed in FIG. 1, the stop plunger 22 is shifted away from the path of the lug 23 and the belt shifter is moved so that the belt runs on a pulley 27 fast on the main shaft to establish the sewing machine drive. As is conventional in buttonhole sewing machines, the stop motion frame may be latched in the position establishing the sewing machine drive and the latch released to stop the sewing machine by a timing device such as a cam means timed to initiate stoppage of the machine after completion of the buttonhole.

The traveling work holder 14 carries brackets 30 having rollers 31 associated therewith disposed in engagement with a guide rail 32 fixed relatively to the support plate 13. Also secured to the traveling work holder is a chain 33 disposed in a track 34 fixed relatively to the support plate 13. The chain 33, at each side of the traveling work holder, is directed over pulleys 35 and 36 on the support plate or set disposed at each side of the sewing unit, and the chain extending from each side of the traveling work holder is also directed over an idler pulley 37 in the cabinet 11. One extremity of the chain is secured to a carriage 33 guided in vertical ways 39 in the cabinet and driven by the indexing mechanism in the cabinet while the other extremity of the chain has a counterweight (not shown) secured thereto.

The sewing machine indexing mechanism and traveling Work holder arrangement thus far described may be constructed in accordance with the disclosure of the referenced Kelemencky patent application Ser. No. 829,394, now Patent No. 3,053,204, as well as the means for effecting alternate indexing and sewing operations.

The traveling work holder 14 thus far described, however, differs from that of the Kelemencky disclosure in that the guide rail 32, guide track 34, and pulleys 35 and 36 are carried by the support plate 13 without those provisions for motion relatively to the support plate as exist in the Kelcmencky disclosure. In the present invention, therefore, the traveling work holder 14 moves in a path which is fixed relatively to the sewing machine 12 and to the cabinet 11.

Referring to FIG. 3, a pair of work grippers 50-51 are arranged in spaced relation and are fulcrumed each at 52 to the traveling work holder 14 or preferably to suitable brackets secured to the traveling work holder. Each of the work grippers 50-51 may be formed as disclosed in the referenced Kelemencky patent including a handle 53 which when depressed closes the gripper and when raised releases the gripper. Secured on the traveling work holder adjacent to each of the grippers 50-51 is a stop block 54 determining an operative indexing position of each of the grippers.

Pivoted, as at 55, to each of the grippers is a twopart link 56, one part being slotted as at 57 and the two parts secured together by fastening screws 58 through the slot so as to provide for a length adjustment of each link. The links 56-56 are pivoted, as at 69 and 61, to opposite arms 62 and 63 of a three armed lever fulcrumed at 64 to the traveling work holder and formed with an operating arm 65. When the three armed lever is turned clockwise, as viewed in FIG. 3, the grippers 50-51 will be turned toward each other thus providing slack in any work fabric gripped therebetween. When the three armed lever is turned counterclockwise, as viewed in FIG. 3, the grippers will be returned to operative indexing position against the respective stop blocks 54, thus making taut any work fabrics gripped therebetween.

For operating the three armed lever 62, 63, 65 in any position of the traveling work holder 14, there is secured to the support plate 13 a pair of spaced hangers 70 in which is journaled a rock frame comprising a rod 71 journaled in the hangers 70, a pair of rock arms 7272 secured to the rod 71 and a rod 73 extending between the rock arms substantially parallel to and above the rod 71.

Referring to FIG. 4, the operating arm 65 of the three armed lever has pivoted to it at 74 a link 75 also pivoted at 76 to an angle bracket 77 secured by screws 78 to a slide bar 79 having an upturned extremity 80. The slide bar 79 is slotted as at 81 and is slidably constrained relatively to the traveling work holder 14 by a pair of shouldered screws 82 passing through the slot 81 and threaded into the traveling work holder. The space between the bracket 77 and the upturned extremity 80 of the slide bar provides a bifurcated jaw embracing the upper rod 73 of the rock frame 71, 72, 73 so that regardless of the position of the traveling work holder, the rock frame 71, 72, 73 can operate the three armed lever 62, 63, 65.

Referring to FIGS. 1 and 3, a rock arm 90 fast on the rod 71 of the rock frame is pivoted at 91 to a two part link 92 of which the parts are adjustably secured together by means of the slots 93, 93 and screws 94, 9 The link 92 is pivotally connected as at 95 to a system of three inter-connected levers of the first class, each fulcrumed on a supporting block 96 on the support plate 13. Of the three interconnerted levers, a lever 97 is fulcrumed as at 98 on a horizontal axis, and levers 99 and 100 are fulcrumed at 101 and 102 respectively on vertical axes. The lever 100 is pivotally connected as at 103 to an arm 104 formed on the stop motion frame beneath the fulcrum 21 of the stop motion frame.

Various other linkages might be used to connect the link 92 to the actuating mechanism of the sewing machine, however, the linkage of the preferred embodiment illustrated in the drawings provides for the proper direc- A, tion of motion of the link 92 in response to motion of the stop motion frame 20, and it provides a means for obtaining the requisite amount of motion at the grippers 5i and 51.

In operation, the movement of the sewing machine stop motion frame 20 out of stopped position will influence a shift of the rock frame 71, 72, 73 so that in any position of travel of the work holder 14 the grippers 50 and 51 will be shifted toward each other to provide slack in a work fabric gripped there'between thus to accommodate movement of the sewing machine work clamp. When the sewing operation is completed and the sewing machine work clamp is released, the movement of the stop motion frame into stopped position will similarly return the grippers '50 and 51 into their original work-tensioning positions ready for indexing of the work fabric.

The work fabrics thus are continuously engaged by the grippers 50 and 51 and proper registry of the work relatively to the traveling work holder is never disturbed during any sequence of sewing and indexing operations. The effort required to slacken the work fabric during sewing is bourne by the stop motion mechanism which is conventionally designed to withstand considerably force concentration and thus is well suited for this purpose. The sewing machine Work clamp is relieved of stress for two reasons, first in not having to shift the traveling work holder as in prior art constructions, and second in having to shift only a small portion of the work fabric, the work fabric adjacent to that portion in the work clamp being free of tension and thus not opposing any shift of the work clamp.

Having thus set forth the nature of this invention what we claim herein is:

1. In a sewing unit including a support, a cyclic sewing machine on said support and having stitch forming instrumentalities, a work clamp shiftable during operation of said stitch forming instrumentalities, and actuating mechanism for imparting cyclic interrelated motion to said stitch forming instrumentalities and said work clamp in the formation of predetermined stitch groups, a traveling work holder including spaced work grippers, means on said support constraining said traveling work holder for movement in a linear path relatively to said sewing machine, and an indexing mechanism for alternately shifting said traveling work holder and initiating operation of said cyclic sewing machine, means for pre venting interference on a work fabric held by said spaced work grippers by the motion of said sewing machine work clamp comprising, means for shiftably supporting said work grippers relatively to said traveling work holder, gripper shifting linkage operatively connecting said work grippers and effective to shift said work grippers from a predetermined spaced relationship toward each other or to return said work grippers to said predetermined spaced relationship, and means operatively connecting said gripper shifting linkage with said mechanism for controlling the cyclic interrelated motion of said stitch forming instrumentalities and said work clamp for shifting said work grippers toward each other prior to stitch formation upon each initiation of operation of said sewing machine and returning said work grippers to said predetermined spaced relationship at the completion of each cycle of sewing machine operation.

2. In a sewing unit including a support, a cyclic sewing machine on said support having a shifta'ble work clamp effective during operation of said sewing machine, and a stop motion mechanism for controlling said cyclic sewing machine operation, a traveling work holder including spaced work grippers, means on said support constraining said traveling work holder for movement. in a linear path relatively to said sewing machine, and an indexing mechanism for alternately shifting said traveling work holder and initiating operation of said cyclic sewing machine, means for preventing interference on a work fabric held by said spaced work grippers by the motion of said sewing machine work clamp comprising, means for shiftably supporting said work grippers relatively to said traveling work holder, gripper shifting linkage operatively connecting said work grippers and effective to shift said work grippers from a predetermined spaced relationship toward each other or to return said work grippers to said predetermined spaced relationship, and means operatively connecting said gripper shifting linkage with said sewing machine stop motion mechanism for shifting said work grippers toward each other prior to stitch formation upon each initiation of operation of said sewing machine and returning said work grippers to said predetermined spaced relationship at the completion of each cycle of sewing machine operation.

3. A device as set forth in claim 1 including a rock frame journaled on said support, a rail provided on said rock frame and disposed substantially parallel to the linear path in which said traveling work holder is constrained for movement, and in which said means operatively connecting said gripper shifting linkage with said sewing machine stop motion mechanism comprises a bifurcated slider shiftably supported on said traveling work holder in a position embracing said rock frame rail and operatively connected to said gripper shifting linkage, and means operatively connecting said rock frame with said sewing machine stop motion mechanism.

4. A device as set forth in claim 1 in which said means for shiftably supporting said work grippers relatively to said traveling work holder comprises fulcrum pins pivotally supporting each of said Work grippers, in which said gripper shifting linkage comprises a three-armed lever pivoted on said traveling work holder between said work grippers and having a pair of diametrically opposed lever arms and an operating lever arm, a pair of links each pivoted to one of said diametrically opposed lever arms and to one of said work grippers, and in Which the means operatively connecting said gripper shifting linkage with said sewing machine stop motion mechanism comprises mechanism operatively connecting said stop 6 motion mechanism with said operating lever arm of said three-armed lever.

5. Sheet material work holding apparatus comprising,

(a) needle means,

(b) means for selectively actuating said needle means to operate on said work,

(0) a pair of clamping devices on opposite sides of said needle means for holding said work in position for operation thereupon by said needle means,

(d) each clamping device comprising a pair of opposed jaws,

(e) means for selectively closing each pair of jaws to hold said work, and opening said jaws to release said work,

(f) means for simultaneously moving each of said clamping devices toward each other to a position wherein the Work held thereby is in a slack condition simultaneously with the actuation of said needle means to operate on the work, and for simultaneously moving said clamping devices away from each other to a work tensioning position while said needle means is inoperative, and

(g) means for moving said work, while said needle means is inoperative, to selectively dilferent positions for operation thereupon by said needle means.

References Cited by the Examiner UNITED STATES PATENTS 1,243,679 10/1917 Allen ll22 1,285,834 11/1918 Stull 269153 X 1,344,748 6/1920 Allen 11276 1,359,712 11/1920 KieWicz 112-75 1,537,155 5/1925 Allen 11276 2,944,496 7/1960 Gardner 1122 X JORDAN FRANKLIN, Primary Examiner.

THOMAS J. HICKEY, DAVID J. WILLIAMOWSKY,

Examiners.

H. D. COOPER, R. V. SLOAN, Assistant Examiners. 

1. IN A SEWING UNIT INCLUDING A SUPPORT, A CYCLIC SEWING MACHINE ON SAID SUPPORT AND HAVING STITCH FORMING INSTRUMENTALITIES, A WORK CLAMP SHIFTABLE DURING OPERATION OF SAID STICH FORMING INSTRUMENTALITIES, AND ACTUATING MECHANISM FOR IMPARTING CYCLIC INTERRELATED MOTION TO SAID STITCH FORMING INSTRUMENTALITIES AND SAID WORK CLAMP IN THE FORMATION OF PREDETERMINED STITCH GROUPS, A TRAVELING WORK HOLDER INCLUDING SPACED WORK GRIPPERS, MEANS ON SAID SUPPORT CONSTRAINING SAID TRAVELING WORK HOLDER FOR MOVEMENT IN A LINEAR PATH RELATIVELY TO SAID SEWING MACHINE, AND AN INDEXING MECHANISM FOR ALTERNATELY SHIFTING SAID TRAVELING WORK HOLDER AND INITIATING OPERATION OF SAID CYCLIC SEWING MACHINE, MEANS FOR PREVENTING INTERFERENCE ON A WORK FABRIC HELD BY SAID SPACED WORK GRIPPERS BY THE MOTION OF SAID SEWING MACHINE WORK CLAMP COMPRISING, MEANS FOR SHIFTABLY SUPPORTING 